Devices designed to set off an alarm responsive to sensing of sounds above a desired level are known. Groff U.S. Pat. No. 4,654,642 discloses a tamper proof classroom noise alarm designed to be located within a classroom and to sound an alarm responsive to sensing of noise above a desired level to control the level of background noise and talking within a classroom. The present invention differs from the teachings of Groff as disclosing both audible and visual alarms which are designed to be activated by crowd noise in a stadium.